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1 year ago

45 The mass of an unidentified metal sphere is 133 grams. Students determine the

Chemistry

1 answer:

Lisa [10]1 year ago

7 0

Answer:

D Cobalt

Explanation:

The volume of the sphere is 40 -25 = 15 cm^3

Density = mass/volume = 133 gm / 15 cm^3 = 8.87 gm/cm^3

which corresponds to Cobalt from the chart

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A chunk of ice breaks off a glacier and falls 30.0 m before it hits the water. Assuming it falls freely (there is no air resista

lina2011 [118]

Answer:

The ice chunk will take 2.47 seconds to hit the water.

Explanation:

Height from which ice chunk fell = h = 30.0 m

Initial velocity of the ice chunk = u = 0 m/s

Time taken by ice chunk to cover 30.0 m of height = t

Acceleration due to gravity = g $9.8m/s^2$

Using second equation of motion ;

$h=ut+\frac{1}{2}gt^2$

$30.0 m=0 m/s\times t+\frac{1}{2}\times 9.8 m/s^2\times t^2$

$t=\sqrt{\frac{30.0m/s\times 2}{9.8 m/s^2}}2.47 s$

The ice chunk will take 2.47 seconds to hit the water.

7 0

2 years ago

A hand-operated conduit bender with a shoe for bending 1-inch EMT can also be used to bend

mixer [17]

If your choices are the following:
A. 1-inch IMC.
B. 1-inch rigid conduit.
C. 3/4 inch IMC.
D. 1/2 inch EMT.

Then the answer is C.

6 0

3 years ago

A scientist wants to make a solution of tribasic sodium phosphate, Na3PO4, for a laboratory experiment. How many grams of Na3PO4

san4es73 [151]

Answer:

83.20 g of Na3PO4

Explanation:

1 mole of Na3PO4 contains 3 moles of Na+.

Mole of Na ion to be prepared = Molarity x volume

= 0.700 x 725/1000

= 0.5075 mole

If 1 mole of Na3PO4 contains 3 moles of Na ion, then 0.5075 Na ion will be contained in:

0.5075/3 x 1 = 0.1692 mole of Na3PO4

mole of Na3PO4 = mass/molar mass = 0.1692

Hence, mass of Na3PO4 = 0.1692 x molar mass

= 0.1692 x 163.94

= 83.20 g.

83.20 g of Na3PO4 will be needed.

3 0

3 years ago

Read 2 more answers

When 61.6 g of alanine (C3H7NO2) are dissolved in 1150. g of a certain mystery liquid X, the freezing point of the solution is 2

MrRissso [65]

Answer:

Explanation:

From the given information:

TO start with the molarity of the solution:

$= \dfrac{61.6 \ g \times \dfrac{1 \ mol \ C_3H_7 NO_3}{89.1 \ g} }{1150 \ g \times \dfrac{1 \ kg}{1000 \g }}$

= 0.601 mol/kg

= 0.601 m

At the freezing point, the depression of the solution is $\Delta \ T_f = T_{solvent}- T_{solution}$

$\Delta \ T_f = 2.9 ^0 \ C$

Using the depression in freezing point, the molar depression constant of the solvent $K_f = \dfrac{\Delta T_f}{m}$

$K_f = \dfrac{2.9 ^0 \ C}{0.601 \ m}$

$K_f = 4.82 ^0 C / m}$

The freezing point of the solution $\Delta T_f = T_{solvent} - T_{solution}$

$\Delta T_f = 7.3^ 0 \ C$

The molality of the solution is:

$= \dfrac{61.6 \ g \times \dfrac{1 \ mol \ NH_4Cl}{53.5 \ g} }{1150 \ g \times \dfrac{1 \ kg}{1000 \g }}$

Molar depression constant of solvent X, $K_f = 4.82 ^0 \ C/m$

Hence, using the elevation in boiling point;

the Vant'Hoff factor $i = \dfrac{\Delta T_f}{k_f \times m}$

$i = \dfrac{7.3 \ ^0 \ C}{4.82 ^0 \ C/m \times 1.00 \ m}$

$\mathbf {i = 1.51 }$

3 0

2 years ago

What mass of H2 is needed to react with 8.75 g of O2 according to the following equation: O2(g) + H2(g) → H2O(g)?

alina1380 [7]

Mass of H₂ needed to react with O₂ : 1.092 g

<h3>Further explanation</h3>

The concentration of a substance can be expressed in several quantities such as moles, percent (%) weight / volume,), molarity, molality, parts per million (ppm) or mole fraction. The concentration shows the amount of solute in a unit of the amount of solvent.

Reaction

O₂(g) + 2H₂(g) → 2H₂O(g)

mass of O₂ : 8.75 g

mol O₂(MW=32 g/mol) :

$\tt \dfrac{8.75}{32}=0.273$